Treatment of cellulosic fibers and fabrics



Patented a. 27, 1925.

UNITED, STATES. PATENT OFFICE.

LESLIE BARRETT, OF WHALLEY RANGE, NEAR MANCHESTER, AND ROBINSON PERCY FOULDS, Olf COLNE, NEAR MANCHESTER, ENGLAND, ASSIGNORS TO TOOTAL. BBOADHUBST LEE COMPANY LIMITED, 01' MANCHESTER, LANCASTER, ENGLAND.

TREATMENT OI CELLULOSIO F THERS AND FABRICS.

N0 Drawing.

To all whom it may concern:-

Be it known that we, FRANK LESLIE BAR- nm'r and Ronmson PnRcY FoULns, both subjects of the King of Great Britain, residing 5 in Whalley Range, near- Manchester, and Colne, near Manchester, in the county of Lancaster and Kingdom of England, respectively, have invented certain new and useful Treatment of Cellulosic Fibers and Fabrics,

of which the following is a specification.

- This invention relates to improvements in the treatment of cellulosic fibers, yarns and fabrics, which may be generically termed textile materials, especially of cotton and more particularly to the process of crping with sulphuric acid of'1.49 1101.55 specific gravity or with sulphuric acid of above 1.55 spec. gr. though we find that'these limits can be slightly varied for the purpos'eof our invention. But the invention relates solely tc such treatment and not to treatments with much more dilute acids or with other mercerizing and the like reagents. It is known in the art that treatment with acid of 1.49 to 1.55 sp. gr. (which may be termed crepingfor brevity) gives an opaque wool-like effect to cotton,-so that it assumes the appearance of crepe. This effect i: quite different from the more transparent or using acid of a specific gravity of over 1.55

which may be termed parchmentizing for brevity.

, According to the invention, in such proc esses we employ as an addition a small quantity of'formaldehyde, its polymers, or any derivatives or condensation product of fornialdehyde which in contact with the parchmentizing (or creping agent) will generate formaldehyde or a'polymer thereof; thus we include hexamethylene tetramine for example but we exclude phenol-formaldehyde resins. V

' It has been found. that by addin up tc 10% or above, of 40% formaldehy e solution, anumber of valuable results are obtained. Forfractical purposes we prefer tc employ an a hit we do notlimit ourselves to the use 01 parchment-like appearance obtained by dition of from one half to onecent of formaldehyde "solution (40%) Application filed April 9, 1928. Serial No. 880,991.

these quantities. The operations of creping and parchmentizing of fibers, yarns and .fabrics as distinct from paper are usually performed at 1016 (l, and we prefer not tc exceed a temperature of 2025 0., as other wise there is danger of the material being tendered.

Although it is convenient to apply the re-. agents simultaneously, they may be used alternately if the conjoint action is thereby obtained,'e. g., if a mixture is by any means produced in contact with the fabric.

The invention is specially useful in the treatment of cellulosic fibers, yarns or fabrics with crping or parchmentizing acid where the material to be treated is-wholly or partly immersed in the chemical agent or a solution thereof, but is also of value where the'creping or parchmentizing acidis applied locally or printed on the surface of the material, as in the production of pattern effects (produced by these means according to the usual well known methods) or where they are applied through a cut stencil in the form of a paste or in a s ray form. In thes( latter cases, control of t e action of the acid is greatly facilitated apd several of the advantages specified below are obtained, the chief of these being (a) The fabric or. other material may be 80 exposed to the action of the agent for a longer period of time without fear'of dam- (b) The penetrative properties of she active agent are very conslderably'increased.

The cellulosic material employed in the treatment may be in the form of fibers, yarns or fabrics of cotton, linen or other simllar substances, artificial silk and the like. It is also possible to apply it to mixed yarns 01 union fabrics composed of any of the above in conjunction with wool, silk, hairs or other fibers for the production of specific effects on .the cellulosic constituents of each mate- 'terial, rovided that the \a'nimal fiber or other a ixtures are not injuriously afiected by the chemical agents employed.

-In the case of fabrics, it may be necessary to employ preliminary or subsequent mechanical or chemical treatment for the pro-' duction of specific effects. The material may be singed on one or both sides before treatment. The material may be mercerized, embossed, calendered, schreinered, beetled, etc., before or'after treatment for the production of specific effects. In some. cases it may be necessary to add or remove sizing materials or other filling substances before creping o1 parchmentizing.

The following effects appear to be obtainable by the use of formaldehyde in an active form along with sulphuric acid under the conditions mentioned above, in the treatment of the cellulosic materials already described.

(1) Formaldehyde modifies the action of sulphuric acid (or parchmentizing strength i. e.,' above 1.55 sp. gr) on cellulosic materials and thus allows of better control of the treatment than would otherwise be the case, since the material may be treated for a longer time.

The addition of even such small amounts as from to 1% of 40% formaldehyde solution to acid of parchmentizing strength, changes or otherwise slows down its action. Thus with a li ht cloth exposure of 20 seconds to (pure acid of 1.70 sp. gr. is too long, as a tender fabric is obtained; if of formaldehyde is present, a good result is obtained with an exposure of 20 seconds.

The precise effect to be obtained'may thus be varied by the time of exposure to the acid. Effects diflicult or impossible. to obtain by the usual parchmentizing process without damage to the fabric may be produced by lengthening the time of the treatments. Effects similar to those resulting from the usual parchmentizing treatment maybe obtained by the process with less fear of damage as greater latitude in the treatment is allowed. On the other hand, it is possible by giving treatments for shorter periods of time, to obtain variediefl'ects. Light cloths treated for these short periods are much softer than those subjected to the usual parchmentizing practice but retain the characteristic transparenc and'on embossing or ealendering, etc. (a ter being suitably conditioned) with a cold or hot surface,'show characteristic effects. I,

The use of formaldehyde in these connectrons thereby facilitates the carrying out of a limited acid treatment, whereby novel andvaluable effects may be obtained.

(2) The formation of so-called amyloid a starchy degradation compound produced during the treatment of cellulosic materials with the usual parchmentizing agents is largely prevented; material subjected to the formaldehyde acid process is therefore usually more transparent than that obtained by theprocess of parchmentizing with'acid alone.

(3) Increased penetration of the parchmentlzmg agent is obtained. This is of considerable value in the treatment of embossed cotton or other fabric for the permanent fixation of the design, as it results in a more marked differential effect with production of a well-defined pattern ,on both sides of the fabric, which is often of value.

(4) The mercerizing properties of yarns and fabrics treated by the new process may differ from those of similar material treated by ordinary agents according to the conditions of treatment: for example, onmercerizing fabric previously subjected to the action of sulphuric acid of parchmentizing strength, the cloth usually assumes a hard transparent character. While it is possible to obtain this effect by mercerizing cloth treated by the new method, mercerization usually takes place more slowly than is otherwise the case, and may be retarded if larger quantities of formaldehyde are used in the acid mixtures during pre-treatment.

(5) The addition of formaldehyde to acid of crping strength (1.49 to 1.55 sp. gr.)

produces novel results. The fabric shrinks considerably'but develops a certain amount of transparency and a slight harshness characteristic of parchmentized material. The effect is distinct from the result produced by 1.54 sp. gr. acid (i. e. below 1.55) without'addition of formaldehyde.

("6) On subjecting fabric treated with sulphuric acid containing formaldehyde, of a strength above 1.55 s gr. to such processes as embossing, calen ering or schreinering, etc., new effects are obtained. These processes produce on fabrics which have been lOU treated long or short periods of time a better'defined pattern or more marked allover effect. The parts subjected to pressure or temperature and pressure, may vary in appearance from dull white to highly lustrous or glazed according to the conditions of mechanical treatement. I

(7) Fabrics treated with acid-formaldehyde of over 1.55 sp. gr. give particularly valuable results if the following procedure is adopted.

Well bleached cloth of any texture, which I has been well singed on one or botlrsides,,

according to the requirements of the finished product, is embossed, calendered, or

otherwise subjected to pressure or to the combined action of heat and pressure inc part or whole, and then treated with a suitable acid-formaldehyde solution as defined above. The treated fabric then possesses in those parts of it which have been subjected to a pressure or combined pressure and heat treatment, a feel which is particularly linenlike in character, it is lustrous even after washing and has the added advantage of being substantially lintless. This is of considerable value in the manufacture of fabrics for various purposes- (8) The usual strength of sulphuric acid for parchmentizin pur oses lies above 1.55 sp. gr. As orma dehyde solution apears to act to some extentas a non-aqueous iluent for sulphuric acid, it is possible to dilute solutions of sulphuric acid to say 1.65 sp. gr. down to 1.525 sp. gr. with 40% formaldehyde solution, and to retain some of the parchmentizing properties of the acid. Dilution to about 1.45 sp. gr. seems to be the limit at which the solution loses its characteristic action on mercerized fabric. Again, the usual lower limit for creping is usually taken at about 1.49 sp. gr. but we find that if a solution of stronger acid is diluted with 40% formaldehyde instead of with water, it is possible to. obtain an appreciable effect "with a mixture whose specific gravity is about 1.45 sp. gr. or even somewhat lower.

. (9) .By addition of formaldehyde to acid of both parchmentizing and creping strengths, it is possible'to treat fibers and yarns of cellulosic materials with greater ease. Hitherto, this has been a very difficult proceeding owing to the rapidity of the action of sulphuric acid'on these materials.

(10) Cellul0sic material if thoroughlytreated by the new process can be'prevented from subsequent shrinkage to a greater extent. than corresponding untreated material.

The process may be applied in combination with any of the" following processes or in any of the following methods (1) Secured or bleached cellulosic fibers,

yarns, or fabric may be treated with agents of creping' or parchmentizing strength containing formaldehyde for suitable periods of time and at suitable temperatures followed by washing, neutralizing, soaping if necessary, and any of the usual finishing processes for the production of plain fabric.

'- (2) The material used maybe previously or subsequently mercerized, or creped, or parchmentized with the usual reagents by any of the usual methodsor a combination of these processes.

(3) Where specific effects, such as'permanent pattern or all over effects are de-,

sired, the material to be treated may, after suitable conditioning, etc., be embossed, cal: endered, or otherwise pressed, with or without heat, or any vcombination of these processes may be employed before treatment which seems to fix any pattern imparted to the fabric if, a parchm'entizing or crepingmixture possessing parchmentizing properties containing formaldehyde is used.

Either of these acid mixtures can be used on light material, for this purpose. Heavy material does not show a well defined perma-.

nent'eflfect by pressure unless parchmentiz ing acid is used. If necessary, such treated material may be subsequently dyed, e. g.,

when colored pattern effects are desired. If

necessary, as already mentioned, the material may be singed-before submission to the chemical treatment.

.,.(4) After treatment of cellulosic materials in any of the aforementioned forms by the process, the treated material, after suitable conditioning may be embossed, calendered, schreinered, gofi'ered or otherwise pressed with or without heat, beetled, etc., for the production of pattern effects, or, in the case of material calendered or subjected tion of all-over effects of varying degrees of lustre.

After such treatment it is usually necessary to submit the materialto a washing process after the mechanical treatment in the case of embossing to remove the relief marks of such mechanical treatment. The material may then be .dyed if necessary.

(5) Fabric or other forms of cellulosic material may be subjected to two consecutive treatments by the process, using creping or parchmentizing mixture ora combination of these; when an increased effect is obtained.

.Such material may then be subjected to any'of the processes enumerated above or to any suitable combination of them. (6) The acid formaldehyde treatment may be applied to the fabric or yarn with or without tension. Also material may, if.

.necessary, be given a previous or subsequent.

treatment with mercerizing soda or ordinary acid of creping strength without ten- Acid treated yarns according to the present invention are important, since according to the invention it is possible to obtain acid treated yarn which is substantially non-tendered.

We declarethat what we claim is:'

1. The process which comprises treating cellulosic textile materials with sulfuric acid of not less than 1.45 spec. grav. in presence of formaldehyde.

to processes of a like nature, for the produc- 2. The process which comprises treating cotton with sulfuric acid 0 between 1;.45 and 1.55spec. grav. inpresence' of formaldehyde at temperatures not higher than 25 C.

7. The process of treating cellulosic fabrics in which the fabrics are treated with sulphuric acid of over 1.45 spec. grav. in presence of formaldehyde and also compressed at a time other than while being treated with said acid.

8. The process of treating cellulosic textile materials with strong sulfuric acid in which formaldehyde is added and the process is stopped at an abnormally early stage but not until the fabric has become more 10 transparent.

In witness whereof we have hereunto signed our names this 14th day of March FRANK LESLIE BARRETT. ROBINSON PERCY FOULDS. 

